* id values of -1 are allowed. They indicate that the id was never
correctly assigned to the async resource. These will appear in any
call graph, and will only be apparent to those using the async_hooks
module, then reported in an issue.
* ids < -1 are still not allowed and will cause the application to
exit the process; because there is no scenario where this should ever
happen.
* Add asyncId range checks to emitAfterScript().
* Fix emitBeforeScript() range checks which should have been || not &&.
* Replace errors with entries in internal/errors.
* Fix async_hooks tests that check for exceptions to match new
internal/errors entries.
NOTE: emit{Before,After,Destroy}() must continue to exit the process
because in the case of an exception during hook execution the state of
the application is unknowable. For example, an exception could cause a
memory leak:
const id_map = new Map();
before(id) {
id_map.set(id, /* data object or similar */);
},
after(id) {
throw new Error('id never dies!');
id_map.delete(id);
}
Allowing a recoverable exception may also cause an abort because of a
stack check in Environment::AsyncHooks::pop_ids() that verifies the
async id and pop'd ids match. This case would be more difficult to debug
than if fatalError() (lib/async_hooks.js) was called immediately.
try {
async_hooks.emitBefore(null, NaN);
} catch (e) { }
// do something
async_hooks.emitAfter(5);
It also allows an edge case where emitBefore() could be called twice and
not have the pop_ids() CHECK fail:
try {
async_hooks.emitBefore(5, NaN);
} catch (e) { }
async_hooks.emitBefore(5);
// do something
async_hooks.emitAfter(5);
There is the option of allowing mismatches in the stack and ignoring the
check if no async hooks are enabled, but I don't believe going this far
is necessary.
PR-URL: https://github.com/nodejs/node/pull/14722
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Trevor Norris